RE: The Questions and Answers Thread (All generations, excluding 5th)
I know that. Is there a specific ratio that the fourth randomized IV will be 31 (with the IV spreads provided)?
For all the IVs that weren't passed down, the odds are 1 in 32 for each one (any one number from 0 to 31).
The IVs passed down in question are random.
Let's say for the sake of example I have a mom with 28 IVs in every stat, and a dad with 25 IVs in every stat. Now for some scenarios. Let's assume I have no Power items.
The IVs passed down for scenario 1 are dad's HP, mom's Atk, and mom's Speed, in that order. The baby will have 28/25/x/x/x/25 IV spread, where x is a random integer from 0 to 31.
The IVs passed down for scenario 2 are dad's HP, mom's Atk, and mom's HP, in that order. The baby will have 25/25/x/x/x/x IV spread.
The IVs passed down for scenario 3 are dad's Sp. Atk, mom's Sp. Atk, and dad's Sp. Atk. The baby will have x/x/x/28/x/x IV spread.
If you use a Power Item (this applies for HGSS-onward), that IV will be sure to pass down and not be overwritten. It will count towards 1 of the 3 which are passed down.